\begin{tikzpicture}
    \tkzDefPoints{0/0/A,  3/0/B,  1/2/D,  4/2/C}
    \tkzInterLL(A,C)(B,D)  \tkzGetPoint{O}

    \tkzDrawPolygon(A,O,B)
    \tkzDrawPolygon(C,O,D)
    \tkzLabelPoints[below](A,B)
    \tkzLabelPoints[above](C,D)
    \tkzLabelPoints[right=0.5em](O)
\end{tikzpicture}

